Studies show that COVID-19 vaccine protection against severe illness remains strong after 6 months.

The COVID-19 vaccine loses some effectiveness in preventing SARS-CoV-2 infection, but the vaccine is severe for up to 6 months, according to an analysis of research literature published last year before the colonization of the Omicron variant. Has almost all of its ability to prevent various diseases. Complete vaccination. the study, View online February 21 LancetWas led by researchers at the Johns Hopkins Bloomberg School of Public Health and the World Health Organization.

For their study, researchers analyzed vaccination efficacy data published on both peer-reviewed journals and preprint servers that submit pre-reviewed articles from June 17 to December 2, last year. Did. The data detailed in 24 papers covered dozens of individual vaccine assessments prior to the emergence of currently predominant Omicron variants.

Researchers found that the level of protection from SARS-CoV-2 infection dropped by an average of about 21 percentage points between 1 and 6 months after complete vaccination, whereas the level of protection against severe COVID-19. Found a slight drop. About 10 percentage points at the same intervals. The authors defined “complete vaccination” as one dose of Janssen vaccine or two doses of other vaccines. The booster dose was not evaluated.

“There are signs here that the effectiveness of the vaccine declines over time, but protection from the most annoying consequences of serious illness seems to work,” said the co-leader of the study. The author, Melissa Higdon, a researcher at the ministry, said. She is a member of International Health at Bloomberg School and a member of the International Vaccine Access Center (IVAC).

How long a vaccine protects against infections and serious illnesses is one of the most urgent issues faced by public health professionals and policy makers in the COVID-19 pandemic. To address this question, researchers have four researchers, Pfizer, Moderna, J & J, and AstraZeneca, published in the journal or posted on the preprint server from June 17th to December 2nd last year. We identified 24 studies targeting major Western-developed vaccines. Many papers included multiple vaccine evaluations. Researchers used statistical tools to combine data from different studies to estimate average changes in vaccine efficacy over time.

The finding that protection against detected infections dropped by an average of 21.0 percentage points in 5 months found that vaccines that provide 90% protection from infection in 1 month provide only 69% protection in 6 months. Means If the analysis was limited to data only, the mean decline was essentially no difference between vaccinated people over the age of 50.

Similarly, protection against symptomatic illnesses from SARS-CoV-2 infection included both mild and severe illnesses, averaging 24.9 percentage points for people of all ages and 32.0 percent points for the elderly. -vaccination.

Public health authorities often emphasize vaccination against severe COVID-19. For this more serious consequence, vaccine protection was clearly more durable, averaging only 10 percentage points lower at 1-6 month intervals. The slight decline was similar in the elderly at high risk of the consequences of severe COVID-19.

Analysis of post-vaccination infections using only delta variants also showed that defenses declined over time. This suggests that weakened immunity, not changes in defense against delta mutants, is the main reason for the reduced efficacy of pre-Omicron waves.

This study is largely in line with others who have long investigated the efficacy of vaccines, with an average of four vaccines being the most serious public health concerns during the pre-Omicron wave. It suggests that it provided excellent protection against the results.

“Because Omicron is still prevalent in many parts of the world, COVID-19-related policy makers pay attention to vaccine efficacy studies in the context of Omicron and future variants to ensure long-term efficacy. It is important to evaluate. The post-vaccination period, including vaccination with booster doses, “Higdon said.